Polycarbonate resins have good mechanical and thermal properties and are thus used in a variety of applications. Particularly, polycarbonate resins can exhibit excellent properties in terms of transparency, hygiene, stiffness, and heat resistance and are thus widely used as a material for medical supplies such as medical devices, surgical instruments, and surgical appliances.
Such medical supplies require sterilization. Sterilization methods include contact treatment using sterilization gases such as ethylene oxide, heat treatment in an autoclave, and irradiation treatment using ionizing radiation such as γ-rays, electron beams, and X-rays.
Ethylene oxide used in contact treatment, however, is toxic and unstable and thus there can be environmental problems with the disposal thereof. Heat treatment in an autoclave can cause degradation of a resin during high temperature treatment and requires high energy costs and a drying process for removing residual moisture from treated components. Thus, irradiation treatment using ionizing radiation, which allows treatment at low temperature and is relatively economical, is generally used for sterilization.
Generally, polycarbonate resins suffer from yellowing and deterioration in physical properties when irradiated with ionizing radiation. To overcome these problems, there have been proposed a method of blending a polycarbonate resin with other polymers, a method of adding various additives to a polycarbonate resin, and a method of copolymerizing a polycarbonate resin. See for example Korean Patent Publication No. 10-2012-0077665.
However, these methods have failed to completely solve problems such as yellowing and deterioration in physical properties.
Therefore, there is a need for a polycarbonate resin composition which exhibits excellent properties in terms of color, transparency, and impact resistance after being irradiated with ionizing radiation such that liquid level or color of contents such as chemicals or blood in a molded article can be easily distinguished.